What is the molarity of a 38 HCl solution. I want to prepare a 0.5M solution from the 38 HCl solution?
I'm not certain what is meant by 38 HCl, but I suspect it must mean 38% HCl. Typically, concentrated Hydrochloric Acid is about 36-38%. 38% W/W means each 100 grams of 38% HCl contains 38 grams of dissolved hydrogen chloride gas. Generally, concentrated HCl is considered to by 12 Formal (or less correctly, 12 Molar) which is equivalent to 12 Normal. A close approximation of 0.5M would be as follows, using a Volume/Volume prep: Combine 11.5 parts water and add 0.5 parts 12 Molar HCl. For example: 115 mL of water plus 5 mL of 12 M HCl.